The parents of Nobel prize-winner Malala Yousafzai have spoken of the attack on their daughter and called it "true cowardice" to not believe in women's freedom.

Toor Pekai and Ziauddin Yousafzai were speaking at the Women in the World conference, and said the moment they found out about the attack was "heart-breaking".

Of their life in Pakistan in 2012 Malala's mother said: "People were getting killed and there was a lot of cruelty - but I wasn't worried because I thought 'she's a young girl and in our culture we are told to respect women'.

"I couldn't imagine that anyone would attack Malala as a child.

"Sometimes when I worried she would tell me 'I can't stop going to school, I can't stop talking, because I am a girl and we cannot go back to the ages when they buried girls alive. I want to progress. I want to speak'.

"And I realised: how can I stop a girl like her from talking or speaking up?"

She added that she was not initially told that her daughter had been shot by the Pakistani Taliban.

"People told me she had an accident - later on I found out from TV that she was attacked, it was heart-breaking.

"I am a mother and you all must have children. I just couldn't imagine what could have happened to her. Still when I remember it is very very hard.

"I was very sad, and I was very upset, but I was more upset for the guys who did it - what would their mothers think? At least I was the mother of a girl of whom I was proud. I was feeling for both sides."

Looking to the future, Malala's father said he was determined that "What my father could not do to my sisters I will do to my daughters."

In a rousing speech on gender equality he said: "Our children will learn what we do, not what we teach.